80 . 



The flora of Mt. Orizaba. By Henry E. Seaton. 



As botanist of the J. T. Scovell expedition during July and August, 1891, 

 collections were made by the writer on Mt. Orizaba through a range of 3,000 

 to 14,000 feet. 



The first collections of importance on the mountain were made by Fred- 

 eriS; Liebmann in 1811. Others who have collected on the mountain, and 

 especially in the valley of Orizaba and Cordoba, are Henri Galeotti, August 

 Ghiesbreght, E. Bourgeau, M. Botteri and Frederick Mueller. The volcano 

 of Orizaba is described by Liebmann as the most interesting mountain in 

 North America. It has a latitude of 18 degrees and lies surrounded by the 

 very fertile country of southern Mexico. It is only ninety miles from the 

 gulf, and having such a situation there is presented upon its eastern slope 

 every phase of vegetation from tropical to alpine. 



The region in the vicinity of Cordoba, at an elevation of 3,000 feet and a 

 distance of sixty miles from the coast, has a sub-tropical vegetation. Palms 

 grow in abundance and orange, banana and coffee trees attain a high de- 

 gree of cultivation. Prominent among the families that make up the 

 shrubby and herbaceous flora are the Malvace*, Leguminosse, Rubiacea', 

 Compositte, Aeclepiadacere, Convolvulacea?, Solanacea?, Euphorbiacea^ and 

 Bromelliacere, besides the grasses, sedges and ferns. 



The town of Orizaba, 1,000 feet higher up the mountain, has a somewhat 

 less tropical vegetation in the way of cultivated plants. At this altitude 

 the Composite have their greatest display. The Helianthoideae are the 

 forms most abundant, and not only are they characteristic of this particular 

 region but have in Mexico their greatest concentration, amounting, it has 

 been estimated, to thirty-two per cent, of the species and two-fifths of the 

 genera of all the Compositse of the country. The sub-order Eupatoriacese 

 ranks second in numerical strength, the genera Eupatorium and Stevia, how- 

 ever, contributing nearly all the species. The Asteroideee, have but little 

 representation in the forms Aster, Erigeron and Solidago, which are so char- 

 acteristic of the north. All the other sub-orders of the family are present 

 excepting the Arctotidefo and Calendulactte, which are confined principally 

 to southern Africa. 



Collections were made at three successively higher stations till the alti- 

 tude of 9,000 feet was reached, and this zone of 5,000 feet above the town of 

 Orizaba may be considered as the temperate region, and that above 9,000 

 feet as alpine. Many plants of the sub-tropical region extend their range 

 to the temperate and even to the alpine district, this being especially true 



